Method of roughening and corrugating the surfaces of grinding-rolls



" UNITED STATES PATENT OFFICE.

HENRY STANLEY, OF ST. LOUIS, MISSOURI.

METHOD OF ROUGHENING AND CORRUGATING THE'SURFACES OF GRINDING-ROLLS.

SPECIFICATION forming part of Letters Patent No. 357,872, dated February15, 1887.

Application filed November 30, 1886. Serial No. 220,328. (No specimenm)To aZZ whom it may concern:

Be it known that I, HENRY STANLEY, of the city of St. Louis, in theState of Missouri, have invented a certain new and useful Method ofRoughening the Surfaces of Grinding-Rolls, of which the following is afull, clear, and exact description.

Whilesmooth chilled-iron rolls are generally used in milling, they canbe improved by a roughened surface, such surface giving better resultsin the manufacturing offiour.

In carrying out my method or process I take a metallic roll, when thegrinding-surface has be n otherwise finished, and treat the surface withdilute nitric acid, which will have the effect of giving a roughness tothe surface very much resembling that of a porcelain roll. Any otheracid or other material may be used that will, by corrosion of the metal,cause the roughening of the surface.

The rollers may have a smooth cylindrical surface before treatment, ormay be corrugated or have any sort of depressions or projections beforetreatment, and the whole of the surface may be treated with theoorroding agent; or any particular pattern orlines, dots, orcorrugations may be etched in the surface of the roll by covering thesurface with some substance which will protect the surface from theaction of the acid, the removal of the substance from the lines, dots,or other parts to allow the dilute acid to act on these parts, and thetreatment with dilute acid.

After the etching of the surface, as above, the surface may be clearedof the protecting substance and the remainder of the grindingsurfaceroughened, if desired, by treatment with the dilute acid or othercorrosive.

I claim as my invention- The treatment of the grinding-surface of ametallic grindingroll with a corrosive or oxidizing material, for thepurpose set forth.

HENRY STANLEY.

In presence of- GEO. H. KNIGHT, EDW. S. KNIGHT.

